Coupling for a multi-part dental implant system

ABSTRACT

A dental implant system having a dental implant, an abutment and a threaded screw is provided. The abutment has a guiding and lock structure and the dental implant has a complementary guiding and lock structure, for associating the abutment to the dental implant, with each guiding and lock structure having an anti-rotational structure. Threaded engagement of the threaded screw to a threaded section of the dental implant is not possible, when the anti-rotational structure of the abutment is held in an intermediate position on the anti-rotational structure of the dental implant, which intermediate position is a position where the longitudinal axes of the guiding and lock structures of the abutment and of the dental implant are coaxial with one another.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application is a continuation application of U.S. patentapplication Ser. No. 11/921,480, filed Jan. 8, 2008, which is theNational Phase of PCT/EP2006/004919 filed May 23, 2006, which claims thebenefit of priority from European Patent Application No. 05104832.0 fileJun. 3, 2005, the entire contents of which are incorporated herein byreference for all purposes.

FIELD OF THE INVENTION

The present invention relates in general to an improved coupling for amulti-part dental implant system and in particular to an improvedcoupling for a dental implant with an abutment, a secondary part or thelike.

BACKGROUND OF THE INVENTION

Generally, multi-part dental implant systems are used in dental surgeryto reconstruct dental parts of a human being. Usually, multi-partimplant systems are comprised of a dental implant, preferably a dentalimplant screw, which is inserted by screwing or pressing into areceiving bore which has been prepared e.g. in the bone tissue andabutments or secondary parts adapted, inter alia, to support a dentalprosthesis.

A frequent problem arising with the above described multi-part dentalimplant systems is the correct positioning of the abutment or thesecondary part within the dental implant already placed in the bonetissue.

The problem of the correct positioning was addressed by numerous priorart patent publications.

In particular, according to U.S. Pat. No. 5,195,852, a cylindricalcavity was devised, at the coronal end of the dental implant screw, toinclude a plurality of striations for preventing the rotation of theabutment supporting a prosthetic structure. However, as the striationswere provided right at the upper end surface of the dental implantscrew, the stability and sterility of the coupling between the abutmentand the dental implant screw was unsatisfactory.

Another solution was proposed by U.S. Pat. No. 5,281,140 wherein a threepart dental implant system comprised of a dental implant, a firstintermediate abutment part and a second distal abutment part wasdisclosed. The dental implant was provided at the coronal end thereofwith a chamfered shoulder, followed by a hexagonal opening extendingapically into the dental implant and followed further apically by aninternally-threaded cylindrical-shaped passage adapted to receive afastener screw. The first intermediate abutment part was shaped at theapical end thereof complementary to the chamfered shoulder and thehexagonal opening of the dental implant, respectively, and provided witha multi-sided projection at its side facing the second distal abutmentpart. Further, the second distal abutment part was shaped at an apicalend thereof with a cavity complementary to the multi-sided projection ofthe first intermediate abutment part, such as to provide for therelative rotational positioning of the two abutments when coupled viathe fastener screw to the dental implant.

Nonetheless, the solution of U.S. Pat. No. 5,281,140 was also not freeof shortcomings due to the larger number of parts involved. Also therelatively large taper degree of the chamfered shoulder was not suitableto provide for a sufficiently stable and sterile coupling of theabutment parts to the dental implant.

EP-A-475 299 discloses a dental implant screw which is connectable to atwo part abutment, wherein the dental implant is provided with centeringand positive lock means spaced from its shoulder and wherein a shortcylindrical recess extends between the centering means and the shoulder.EP-A-475 299, however, also fails to provide for a sufficiently stableand sterile coupling of the abutment parts to the dental implant screw.

SUMMARY OF THE INVENTION

The aim of the present invention is to provide an improved coupling fora multi-part dental implant system and in particular an improvedcoupling for a dental implant with an abutment, a secondary part or thelike which avoids the drawbacks of the prior art devices, and thusallows a stable and sterile coupling between the dental implant and theabutment and the secondary part, respectively.

Within the scope of this aim, an object of the present invention is toprovide an improved coupling for a multi-part dental implant system,wherein the positioning of the abutment or the secondary part can beaccurately performed even by a user who is less experienced. In fact, itwill be appreciated by the person skilled in the art that thepositioning of the abutment or of the secondary part on the dentalimplant is not a trivial matter having regards of the small dimensionsof the parts involved and the working environment. At any rate, thesolution proposed by the present invention to the above object isintended not to be detrimental to sterility and stability of thecoupling.

Another object is to provide an improved coupling for a multi-partdental implant system, wherein the number of parts is minimized.

This aim, these objects and other which will become better apparenthereinafter, are achieved by a coupling for a multi-part dental implantsystem as defined in the appended claims.

In particular, the present invention provides in certain embodimentsthereof for an abutment for use in a dental implant system, wherein theabutment is provided with guiding and lock means for associating theabutment to a dental implant, the guiding and lock means including: afirst conically tapered section; a second substantially non-taperedsection arranged apically adjacent to the first section, the secondsection being provided with anti-rotational means; and a thirdsubstantially circular cylindrical section arranged apically adjacent tothe second section, such that to provide axial guiding to the abutmentupon the insertion thereof into a dental implant. In an analogousmanner, an complementary matter to above, the invention provides for adental implant for use in a dental implant system, wherein the dentalimplant is provided with a guiding and lock means for associating thedental implant to an abutment, the guiding and lock means including: afirst conically tapered section; a second substantially non-taperedsection arranged apically adjacent to the first section, the secondsection being provided with an anti-rotational means; and a thirdsubstantially circular cylindrical section arranged apically adjacent tothe second section, such that to provide axial guiding to an abutmentupon the insertion thereof into the dental implant

In other embodiments of the invention an abutment for use in a dentalimplant system is disclosed, wherein the abutment is provided with aguiding and lock means for associating the abutment to a dental implant,the guiding and lock means including: a first conically tapered section;and a second substantially non-tapered section arranged apicallyadjacent to the first section, the second section being provided with ananti-rotational means, wherein the anti-rotational means of the secondsection includes a surface extending radially with respect to the axisof the abutment and adapted to cooperate with a dental implant, suchthat to provide radial guiding to the abutment upon the insertion intothe implant. In a similar manner the invention also teaches a dentalimplant for use in a dental implant system, wherein the dental implantis provided with a guiding and lock means for associating the dentalimplant to an abutment, the guiding and lock means including: a firstconically tapered section; and a second substantially non-taperedsection arranged apically adjacent to the first section, the secondsection being provided with an anti-rotational means, wherein theanti-rotational means of the second section includes a surface extendingradially with respect to the axis of the dental implant and adapted tocooperate with an abutment, such that to provide radial guiding to theabutment upon the insertion into the implant.

BRIEF DESCRIPTION OF THE DRAWINGS

Further characteristics and advantages of the present invention willbecome better apparent from the following description of a preferred butnot exclusive embodiment of the implant system according to theinvention, illustrated by way of non-limitative example in theaccompanying drawings, wherein:

FIG. 1A is a perspective view of a coupling for a multi-part dentalimplant system according to a first embodiment of the invention;

FIG. 1B is an upper view of a dental implant provided with the couplingaccording to the first embodiment of the invention;

FIG. 1C is a side view of the guiding and lock means of the dentalimplant and the corresponding guiding and lock means of the abutment orthe secondary part according to the first embodiment of the invention;

FIG. 1D is a view of a dental implant assembled with the abutment andincluding the coupling according to the first embodiment of the presentinvention;

FIG. 1E is an overall view of the dental implant system incorporatingthe coupling according to the first embodiment of the present invention;

FIG. 2A is a perspective view of a coupling for a multi-part dentalimplant system according to a second embodiment of the invention;

FIG. 2B is an upper view of a dental implant provided with the couplingaccording to the second embodiment of the invention;

FIG. 2C is a side view of the guiding and lock means of the dentalimplant and the corresponding guiding and lock means of an abutment or asecondary part according to the second embodiment of the invention;

FIG. 3A is a perspective view of a coupling for a multi-part dentalimplant system according to a third embodiment of the invention;

FIG. 3B is an upper view of a dental implant provided with the couplingaccording to the third embodiment of the invention;

FIG. 3C is a side view of the guiding and lock means of the dentalimplant and the corresponding guiding and lock means of an abutment or asecondary part according to the third embodiment of the invention;

FIG. 4A is a perspective view of a coupling for a multi-part dentalimplant system according to a fourth embodiment of the invention;

FIG. 4B is an upper view of a dental implant provided with the couplingaccording to the fourth embodiment of the invention;

FIG. 4C is a side view of the guiding and lock means of the dentalimplant and the corresponding guiding and lock means of an abutment or asecondary part according to the fourth embodiment of the invention;

FIG. 5A is a perspective view of a coupling for a multi-part dentalimplant system according to a fifth embodiment of the invention;

FIG. 5B is an upper view of a dental implant provided with the couplingaccording to the fifth embodiment of the invention;

FIG. 5C is a side view of the guiding and lock means of the dentalimplant and the corresponding guiding and lock means of an abutment or asecondary part according to the fifth embodiment of the invention;

FIG. 6A is a perspective view of a coupling for a multi-part dentalimplant system according to a sixth embodiment of the invention;

FIG. 6B is an upper view of a dental implant provided with the couplingaccording to the sixth embodiment of the invention; and

FIG. 6C is a side view of the guiding and lock means of the dentalimplant and the corresponding guiding and lock means of an abutment or asecondary part according to the sixth embodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION

With reference to the enclosed FIGS. 1A through 1E there is shown adental implant 1, preferably a dental implant having an external threadfor insertion into a bone tissue, an abutment or secondary part 2 and athreaded fastener screw 3 forming together a dental implant system. Thethreaded fastener screw 3 is preferably axially hold in the abutment, asbest seen in FIG. 1D.

According to the first embodiment of the present invention, the abutment2 is provided with guiding and lock means implemented as a firstconically tapered section 7, followed, in a further apical position, bya second substantially non-tapered section 4 with protrusions 4′extending in an axial direction of the abutment 2 and followed, infurther remote apical position, by a third substantially circularcylindrical section 22.

The number of protrusions shown in FIGS. 1A through 1E is equal toeight. This results in a substantially octagonal cross-section of thesecond non-tapered section 4. Nevertheless, the person skilled in theart will appreciate that the number of protrusions may be varied as needbe to adjust the number of relative positions between the dental implant1 and the abutment 2. Also the shape of the protrusions 4′ may bevaried, such that the resulting cross-section of the respective abutmentsection is not necessarily octagonal.

According to the present first embodiment, it has been found that it isparticularly advantageous if the axial extension of second section 4 isabout twice the axial extension of the third section 22. Further, it hasbeen found that it is particularly advantageous if the axial extensionof the first section 7 is approximately equal to the overall axialextension of the second 4 and third 22 sections taken together.Therefore, the user is provided with a longer insertion path andconsequently with a better feedback when assembling the abutment to thedental implant. In addition, the fastening (or threading) of the screw 3to a dental implant is only possible once the second section 4 alongwith the third section 22 are fully inserted into their complementarysections of the dental implant, as will be described hereinafter. Inthis way a wedging of the screw can be avoided.

According to the present invention, it has also been found that thetaper of the first section 7 with respect to the axis of the abutment 2is in the order of about 6° to about 10°, preferably about 7° to about9° and most preferably about 8° such that sealing and stabilityrequirements of the coupling between the dental implant and the abutmentare met. In addition, it has been found that the axial extension of thefirst section 7 is preferably, as explained, in the order of about theoverall axial length of the second 4 and third 22 sections takentogether. The latter also further improves the sealing and stabilitycharacteristic of the dental implant system of the present invention.

The dental implant 1 is provided with guiding and lock means that arecomplementary to the guiding and lock means of the abutment 2, namely afirst conically tapered section 7′ matching the first conically taperedsection 7 of the abutment 2, a second substantially non-tapered section4″ with grooves 4′″ adapted for receiving the second substantiallynon-tapered section 4 and the protrusions 4′ of the abutment 2, and athird substantially circular cylindrical section 22′ adapted forreceiving the third section 22 of the abutment. As the first 7′, second4″, and third 22′ sections of the dental implant 1 are, as set forthabove, complementary to the first 7, second 4, and third 22 sections ofthe abutment 2 as regards shape, extension, taper angle etc., thedetailed description thereof will be omitted for the sake of avoidingrepetitions. Nonetheless, the person skilled in the art will appreciatethat the number of protrusions must not equate the number of grooves, asalso apparent from some of the embodiments described hereinbelow.

According to the present invention the shoulder 8 of the dental implant1 is free of grooves and the grooves/protrusions providing for theanti-rotation lock between the dental implant 1 and the abutment 2 aredisplaced from the shoulder 8. Therefore, the sealing characteristics ofthe dental implant system at the interface between the dental implantand the abutment are not impaired and the sterility thereof ismaintained. In addition, the jamming of the protrusions 4′ is avoidedupon the insertion of the abutment 2 into the dental implant 1 due topresence of the first tapered sections 7 and 7′.

Moreover, by means of the taper fitting, an efficient anti-bacterialbarrier is created as no micro gap is present between the dental implant1 and the abutment 2 and the exact matching of the latter parts hindersrelative micro displacements therebetween. Further, by tightening thefastener screw 3, a double anti-rotation lock is achieved, namely apositive lock by means of the protrusion/groove interaction and africtional lock by means of the interaction between two tapered sections7 and 7′.

Furthermore, the third sections 22 and 22′ of the abutment 2 and dentalimplant 1, respectively, provide for a guiding function that facilitatesthe insertion of the abutment 2 into the dental implant 1.

It should be noted that the advantages listed above apply to all of theembodiments described herein, although the guiding function may beachieved in a different manner to be described hereinbelow.

A second embodiment of the present invention is described with regard toFIGS. 2A through 2C wherein features similar to those of the firstembodiment of the invention are designated by the same referencenumerals, and therefore the description thereof will be omitted to theextent of the overlap with the first embodiment of the invention.

In the second embodiment, the second and the third sections of theabutment 2 are replaced by a protrusion 24′ that is provided apicallyadjacent to the first section 7 thereof. For the sake of betterunderstanding the abutment is also shown in an inverted view in FIG. 2A.

In the dental implant 1 of the second embodiment the second and thirdsections are, in turn, replaced by an annular platform 5 with grooves24′″ which provide for a rosetted appearance to the guiding and lockmeans of the dental implant 1. While four grooves 24′″ are shown inFIGS. 2A and 2B, the person skilled in the art will readily understandthat their number can be varied as need be, for instance to adjust thenumber of relative positions between dental implant and abutment.

The improved handling of the second embodiment of the invention isachieved by placing the abutment 2 with its protrusion 24′ on theannular platform 5 of the dental implant 1 in an intermediate position.In this position it is not possible to tighten the fastener screw 3.Therefore, an improved jamming safety is provided to the abutment.Tightening of the fastener screw 3 is only possible if the protrusion24′ is rotated until it is brought in registration with one of thegrooves 24′″ and fully penetrates it. In this way, the second embodimentof the invention provides for an advantageous implementation of theguiding function that facilitates the insertion of the abutment 2 intothe dental implant 1.

A third embodiment of the present invention is described with regard toFIGS. 3A through 3C wherein features similar to those of the firstembodiment of the invention are designated by the same referencenumerals, and therefore the description thereof will be omitted to theextent of the overlap with the first embodiment of the invention.

In the abutment of the third embodiment of the invention, the secondsection 34 is implemented with a substantially octagonal cross-section,with four straight sides connected by four interposed protruding sides,each of the protruding sides having preferably a curved shape. In fact,expressed in an exaggerated manner, the cross-section resembles to asquare with rounded edges. The substantially cylindrical third section22 of the abutment 2 is similar to the third section 22 of the abutmentof the first embodiment.

In the third embodiment of the invention, the second section of thedental implant 1 is replaced yet again by a platform 35 with fourgrooves 34′″ which provide for the above described square appearancewith rounded edges to the guiding and lock means of the dental implant1. In other words, the outline or the cross-section of the platform 35and the grooves 34′″ of the dental implant is complementary to theoutline or cross-section of the second section 34 of the abutment 2. Thethird section 22′ of the dental implant is complementary to the thirdsection 22 of the abutment 2.

The improved handling of the third embodiment of the present inventionis achieved by placing the abutment 2 with its second section 34(forming the square outline with rounded edges) on the platform 35 ofthe dental implant 1 in an intermediate position, such that the straightsides of the second section 34 of the abutment 2 rest on the platform 35of the dental implant. In this position it is not possible to tightenthe fastener screw 3. Therefore, an improved jamming safety is providedto the abutment. Tightening of the fastener screw 3 is only possible ifthe second section 34 of the abutment 2 is rotated into registrationwith the grooves 34′″. In this way, the third embodiment of the presentinvention provides for an advantageous implementation of the guidingfunction that facilitates the insertion of the abutment 2 into thedental implant 1. Furthermore, the guiding function is enhanced by thepresence of the respective third sections on the abutment and dentalimplant.

A fourth embodiment of the present invention is described with regard toFIGS. 4A through 4C wherein features similar to those of the thirdembodiment of the invention are designated by, the same referencenumerals, and therefore the description thereof will be omitted to theextent of the overlap with the third embodiment of the invention.

In the fourth embodiment of the invention the abutment 2 is providedwith eight protrusion 44′ (forming a substantially octagonal outline)while the dental implant 1 is provided with eight matching grooves 44′″(also forming a substantially octagonal outline) and adapted to receivethe protrusions 44′. Again, it is stressed that the number ofprotrusions and of the matching grooves can be varied as need be.

Advantageously, in the fourth inventive embodiment, there is providedaround the grooves 44′″ a SCS-ring 10 which functions as a forcetransmission element. Thus, the grooves 44′″ of the dental implant 1serve only as (rotational) positioning or repositioning elements and arenot subjected to stress due to force transmission.

A fifth embodiment of the present invention is described with regard toFIGS. 5A through 5C wherein features similar to those of the firstembodiment of the invention are designated by the same referencenumerals, and therefore the description thereof will be omitted to theextent of the overlap with the first embodiment of the invention.

In the fifth embodiment of the invention the abutment 2 is provided withthree protrusions 54′ (forming a substantially triangular outline) whilethe dental implant 1 is provided with three matching grooves 54′″ (alsoforming a substantially triangular outline) and adapted to receive theprotrusions 54′. Such substantially triangular outline allows a betterforce transmission.

Moreover, in a similar manner to the second inventive embodiment, thereis provided an annular platform 55 surrounding the grooves 54′″.Accordingly, in a similar manner to the second embodiment an improvedjamming safety is provided to the abutment 2, as the abutment 2 is heldin an intermediate position on the annular platform 55 until theprotrusions 54′ are rotated into registration with the grooves 54′″ suchthat the abutment 2 fully penetrates the dental implant 1 and may befirmly fastened by the fastener screw 3 thereto.

A particular feature of the fifth embodiment is the extended cylindricalthird section designated by reference numeral 11 provided at the apicalend of the abutment 2 adjacent to the second non-tapered section, theextended cylindrical third section 11 providing, in conjunction with amatching third section 12 in the dental implant 1, for a better supportand guiding of the abutment 2. Preferably, the axial extension of theextended third section 11 of the abutment is such that the ratio thereofto the axial extension of the second section of the abutment 2 is fromabout 1.4 to 1.7 and more preferably 1.6. As can be seen with particularreference to FIG. 5C the axial extension of the first section of theabutment is about one half of the axial extension second sectionthereof.

A sixth embodiment of the present invention is described with regard toFIGS. 6A through 6C wherein features similar to those of the firstembodiment of the invention are designated by the same referencenumerals, and therefore the description thereof will be omitted to theextent of the overlap with the first embodiment of the invention.

In the sixth embodiment of the invention the abutment 2 is provided withone single protrusion 64′ while the dental implant 1 is provided with aplurality (e.g. four) matching grooves 64″ and adapted to receive theprotrusion 64′.

Further, in a similar manner to the second or fifth inventiveembodiment, there is provided an annular platform 65 interposed betweenthe grooves 64′″. Thus, an improved jamming safety is provided to theabutment 2, as the abutment 2 is held in an intermediate position on theannular platform 65 until the protrusion 64′ is rotated intoregistration with one of the grooves 64′″ such that the abutment 2 fullypenetrates the dental implant 1. Also, the guiding and support functionin the sixth embodiment is enhanced by the presence of the respectiveextended third sections on the abutment and dental implant, wherein thesections are devised to have an axial extension similar to that of thefifth embodiment.

Clearly, several modifications will be apparent to and can be readilymade by the person skilled in the art without departing from the scopeof the present invention. Therefore, the scope of the claims shall notbe limited by the illustrations or the preferred embodiments given inthe description in the form of examples, but rather the claims shallencompass all of the features of patentable novelty that reside in thepresent invention, including all the features that would be treated asequivalents by the person skilled in the art. In this regard it isstressed that the dental implant and abutment of the invention can bemanufactured from ceramics, metal (in particular titan) and combinationsthereof.

Where technical features mentioned in any claim are followed byreference signs, those reference signs have been included just for thesole purpose of increasing intelligibility of the claims andaccordingly, such reference signs do not have any limiting effect on thescope of each element identified by way of example by such referencesigns.

The invention claimed is:
 1. A dental implant system comprising a dentalimplant, an abutment and a threaded screw, the abutment comprising aguiding and lock means and the dental implant comprising a complementaryguiding and lock means, for associating the abutment to the dentalimplant, the guiding and lock means of the abutment comprising anon-tapered section provided with an anti-rotational means, wherein theanti-rotational means comprises a surface extending radially withrespect to a longitudinal axis of the abutment and being adapted tocooperate with the dental implant to provide rotational guiding to theabutment upon insertion of the abutment into the dental implant, and thecomplementary guiding and lock means of the dental implant comprising anon-tapered section provided with an anti-rotational means, wherein theanti-rotational means of the dental implant comprises a surfaceextending radially with respect to a longitudinal axis of the dentalimplant and being adapted to cooperate with the abutment to providerotational guiding to the abutment upon insertion of the abutment intothe dental implant, wherein the dental implant further comprises athreaded section arranged apically to the non-tapered section of thedental implant, wherein the abutment is adapted to axially hold thethreaded screw for fastening the abutment to the dental implant, andwherein threaded engagement of the threaded screw to the dental implantis not possible when the anti-rotational means of the abutment is heldin an intermediate position on the anti-rotational means of the dentalimplant, wherein the intermediate position is a position where thelongitudinal axes of the guiding and lock means of the abutment and ofthe dental implant are coaxial with one another.
 2. The dental implantsystem according to claim 1, wherein the guiding and lock means of theabutment further comprises a conically tapered section disposedcoronally of the non-tapered section of the guiding and lock means ofthe abutment; and wherein the complementary guiding and lock means ofthe dental implant further comprises a conically tapered sectiondisposed coronally of the non-tapered section of the complementaryguiding and lock means of the dental implant.
 3. The dental implantsystem according to claim 2, wherein the taper of the conically taperedsection of the guiding and lock means of the abutment with respect tothe axis of the abutment is about 6° to about 10°.
 4. The dental implantsystem according to claim 1, wherein the guiding and lock means of theabutment further comprises a substantially circular cylindrical sectiondisposed apically of the non-tapered section of the guiding and lockmeans of the abutment; and wherein the complementary guiding and lockmeans of the dental implant further comprises a substantially circularcylindrical section disposed apically of the non-tapered section of thecomplementary guiding and lock means of the dental implant.
 5. Thedental implant system according to claim 1, wherein the anti-rotationalmeans of the guiding and lock means of the abutment comprises at leastone protrusion.
 6. The dental implant system according to claim 1,wherein the anti-rotational means of the complementary guiding and lockmeans of the dental implant comprises an annular platform.
 7. The dentalimplant system according to claim 6, wherein the annular platform issurrounded by four grooves.
 8. The dental implant system according toclaim 1, wherein the non-tapered section of the guiding and lock meansof the abutment comprises four straight sides connected by fourinterposed protruding sides.